Molecular dynamics simulation study of primary damage in UO2 produced by cascade overlaps

Molecular dynamics (MD) simulation is used to simulate the primary damage state due to α-self-irradiation in a UO2 matrix. This study is carried out by simulating a set of 5 keV displacement cascades. Primary knock-on atom (PKA) direction and temperature are found not to influence the creation of point defects and point defects clustering. In the cascade overlap sequences the number of point defects created saturates as the dose increases. Large clusters of vacancies are observed toward the end of the overlap sequences. These clusters are stable within the time scale of the MD simulations. Interstitial clusters are found to be small and isolated.